Oscillating arm apparatus for manufacturing a tire reinforcement from a single cord

ABSTRACT

An oscillating arm apparatus for manufacturing a tire reinforcement from a single cord in which the cord is deposited in contiguous arches on a rigid core by a system of arms arranged in series conveying an eyelet in such a way as to allow it to traverse a core and thus deposit adjacent arches.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to the manufacture of tires. More precisely, it relates to the depositing of cords to constitute a tire reinforcement. More particularly, it proposes means suitable for manufacturing such a reinforcement on a form similar or identical to the form of the internal cavity of the tire, that is to say a substantially toroidal form, supporting the tire blank during manufacture thereof.

[0002] In this technical field, processes and apparatus are already known which permit incorporation of the manufacture of the tire reinforcements into assembly of the tire itself This means that, rather than having recourse to semi-finished products, such as reinforcement plies, one or more reinforcements are produced in situ, at the time of manufacture of the tire, from a cord spool. Of these processes and apparatus, the solution described in U.S. Pat. No. 5,453,140 is most particularly adapted to the production of carcass reinforcements on a rigid core, the outer surface of which corresponds substantially to the form of the internal cavity of the finished tire. This patent discloses equipment in which the cord, intended to constitute a carcass reinforcement, is laid down in contiguous arches on a rigid core, via an eyelet fixed on a chain mounted on pulleys in such a way as to surround the core by forming a type of fork. The eyelet performs a to-and-fro movement around the core in such a way as progressively and contiguously to lay down an arch with each outward movement and an arch with each return movement, suitable pressers being used to apply the ends of said arches as they are formed on the rigid core pre-coated with uncured rubber.

[0003] The object of the present invention is to provide equipment variants for depositing a reinforcing cord on a core in substantially the same manner.

SUMMARY OF THE INVENTION

[0004] The invention proposes an apparatus for manufacturing a tire reinforcement, said apparatus being intended for manufacturing a reinforcement constituted from a cord supplied continuously and on demand by a suitable distributor, said apparatus being intended for use in cooperation with a substantially toroidal form on which said reinforcement is built up progressively by laying down arches of said cord, according to a desired trajectory for said cord, on the surface of said form, said apparatus comprising:

[0005] a guide member in which the cord may slide freely,

[0006] means of displacing said guide member in a cyclical, to-and-fro, movement, to bring said guide member in successive cycles into the vicinity of each of the desired ends for the cord in said trajectory,

[0007] pressers close to each end of said trajectory, for applying the cord onto the form at said ends,

[0008] characterized in that:

[0009] the displacement means comprises at least one base arm, said base arm comprising a center of rotation and a conveying head, and control means for imparting to said base arm an oscillatory movement about said center of rotation, the apparatus being arranged so that the conveying head of said base arm directly or indirectly conveys the guide member from one end to the other of said trajectory,

[0010] the geometric axis of said center of rotation is, in the working position, entirely exterior to the form.

[0011] Reference can be made to the above-cited patent, since the present invention includes not only the process described therein but also to a considerable extent the pressers used to allow formation of a loop and to apply said loop against the core. By way of a reminder, the pressers essentially each comprise a fork and a hammer. Apart from a few details, the presser embodiment described therein could be used as it is, even through a novel form is proposed below for said pressers.

[0012] The main differences provided by the invention lie in the cord depositing members and more precisely the actuation of said guide member in which the cord may slide freely (i.e. the eyelet). In other words, the oscillating arm system or systems described below are designed to be able to replace the chain system described in the above-cited patent.

[0013] Before embarking on a detailed description of these novel means of actuating the cord guide member, it would be helpful to remember certain useful points.

[0014] First of all, it should be noted that, as in the above-cited patent, the term “cord” must be understood in a completely general sense, covering a monofilament, a multifilament, an assembly such as for example a cable or a plied yarn, or a small number of grouped cables or plied yarns, whatever the nature of the material and whether or not the “cord” is pre-coated with rubber. In the present specification, the term “arch” is used to designate a portion of cord extending from a singular point to another in the reinforcement armature. All these arches disposed over the entire periphery of the tire form the reinforcement proper. An arch as defined here may be part of a carcass or of a crown reinforcement or of any other type of reinforcement. These arches may be separated by cutting the cord during laying thereof, or they may all be connected together in the finished reinforcement, for example by loops.

[0015] Basically, the invention relates to continuous laying of a reinforcing cord, in a configuration as close as possible to the configuration in the finished product. Since the cord is supplied on demand by a suitable distributor comprising, for example, a cord spool and, if applicable, a device for controlling the tension of the cord withdrawn from the spool, the apparatus for manufacturing a reinforcement from a cord cooperates with a form (rigid core or reinforced membrane) on which the tire is manufactured. It is of little significance whether the reinforcement, to be complete, is fabricated in several successive passes of the depositing members described with or without cutting of the cord between two passes.

[0016] When positions or directions are defined by the words “radially, axially, circumferentially” or when radii are mentioned, the reference point is taken to be the core on which the tire is manufactured, or the tire itself, which comes to the same thing. The geometric axis of reference is the axis of rotation of the form.

[0017] Likewise, as has already been pointed out in the above-cited patent, the cord depositing members described here also allow the production of a reinforcement, for example a carcass reinforcement, in which the laying pitch of the cord is variable. “Laying pitch” is understood to mean the distance resulting from the sum of the space between two adjacent cords and the diameter of the cord. It is well known that, for a carcass reinforcement, the space between cords varies according to the radius at which it is measured. This is not the variation referred to here, which is a variable pitch at a given radius. For this, it is sufficient to vary the speed of rotation of the form as a function of any suitable law without changing the working speed of the guide member. A tire is thus obtained, the carcass reinforcing cords of which, for example for a radial carcass, are disposed at a pitch exhibiting controlled variation for a given radial position.

[0018] Various embodiments of the invention may be envisaged. Three main embodiments will be described below. The first embodiment uses a series of three functional oscillating arms. In addition, possible variants are described for this first embodiment. A series of three functional oscillating arms is preferably used for depositing carcass arches extending from one bead to the other of the tire. The second embodiment uses a series of two functional oscillating arms. Furthermore, a variant embodiment is given for this second embodiment. A series of two functional oscillating arms is used, for example, for depositing carcass arches extending from a bead to a shoulder of the tire. The third embodiment uses a single functional oscillating arm, which is sufficient for the simplest laying down to be performed.

[0019] When “n” functional oscillating arms are used which are arranged in series (n>1), the term “n^(th) arm” is used to designate the functional oscillating arm to which the cord guide member is directly fixed, the base arm always being the “first oscillating arm”. The oscillating arms are arranged in series in such a way that, in general, the conveying head of the oscillating arm “p” (p being<n) conveys the center of rotation of the oscillating arm “p+1”. This is why it is stated above that the conveying head conveys the cord guide member directly, or only “indirectly” (that is to say through the intermediary of one or more other functional oscillating arms). In all the examples described, the geometric axis of the center of rotation of the first oscillating arm is, in the working position, entirely exterior to the form, with which it never comes into contact, that is to say not even via its extensions.

[0020] The apparatus causes the cord guide member to describe a movement which is substantially included in a plane—the plane of movement—perpendicular to the geometric axis of rotation of the base arm. In another aspect of the apparatus according to the invention, the base arm, or according to the variants, each of the oscillating arms used, is of planar, long-limbed appearance, and the base arm oscillates in this plane of movement, or all the oscillating arms move in parallel, neighboring planes, one of them being very close to this plane of movement, or even merged with this plane of movement, depending on the type of guide member used.

[0021] It should also be pointed out that, in another aspect, and without taking account of the respective position of the series of oscillating arms with respect to the form, the invention proposes an apparatus for manufacturing a tire reinforcement comprising a series of arms articulated with one another, the articulations being perpendicular to the plane of movement. Said apparatus, intended for manufacturing a reinforcement constituted from a cord supplied continuously and on demand by a suitable distributor and intended for use in cooperation with a substantially toroidal form on which said reinforcement is built up progressively by depositing arches of said cord according to a desired trajectory for said cord on the surface of said form, comprises:

[0022] a guide member in which the cord may slide freely,

[0023] means for displacing said guide member in a cyclical, to-and-fro, movement, to bring said guide member in successive cycles into the vicinity of each of the desired ends for the cord in said trajectory,

[0024] pressers close to each end of said trajectory, for applying the cord onto the form at said ends,

[0025] characterized in that the displacement means comprise at least two arms, i.e. an oscillating base arm and at least one other oscillating arm, said at least two arms each comprising a center of rotation and a conveying head, said at least two arms each oscillating about a geometric axis of rotation, said geometric axis of rotation being parallel to each other, and control means for imparting to said arms oscillatory movements about the respective geometric axes of rotation thereof, the apparatus being arranged so that the conveying head of said base arm conveys the center of rotation of a second oscillating arm and so that the conveying head of the second oscillating arm directly or indirectly conveys the guide member from one end to the other of said trajectory.

[0026] The description which follows affords a full understanding of all the aspects of the invention.

DESCRIPTION OF THE DRAWINGS

[0027]FIG. 1 is a schematic perspective view showing a first embodiment of an apparatus according to the invention;

[0028]FIG. 2 is a detail of a presser of this apparatus;

[0029]FIG. 3 illustrates a first variant of the first embodiment;

[0030]FIG. 4 shows in more detail a stage of operation of the apparatus according to the first embodiment;

[0031]FIG. 5 illustrates a detail of the first embodiment which is not visible in FIG. 1;

[0032]FIG. 6 illustrates a second variant of the first embodiment;

[0033]FIG. 7 shows the successive stages of operation of the second variant of the first embodiment;

[0034]FIG. 8 is a radial section showing a second embodiment of an apparatus according to the invention;

[0035]FIG. 9 illustrates a variant of the second embodiment;

[0036]FIG. 10 is an elevational view (section in the plane defined in FIG. 1 by the axis MM and the geometric axis of the shaft 3D, also called the “median plane”) of the control mechanism used in the first embodiment illustrated in FIG. 1;

[0037]FIG. 11 is a section along AA in FIG. 10;

[0038]FIG. 12 is a schematic perspective view showing a third embodiment of an apparatus according to the invention;

DESCRIPTION OF PREFERRED EMBODIMENTS

[0039]FIG. 1 (as moreover for all the examples described, without this being limiting) shows that the form is a core 1 (rigid and dismantlable) defining the geometry of the inner surface of the tire. This is coated with rubber 10 (see FIG. 7), for example a butyl rubber-based sealing rubber layer and a rubber layer ensuring coating of the carcass cords. The rubber 10 covering the core 1 allows a cord 4 to be held on the core 1 as it is deposited thereon, by an adhesive effect. The core 1 is driven rotationally by any suitable device, not shown.

[0040] The depositing members proper essentially comprise a system of oscillating arms 3 ^(1a) on the one hand and presser devices 2 ^(G) and 2 ^(D) on the other. With regard to the reference numerals in the Figures, the convention used is to designate similar members with the same main reference numerals, for example “3” for the system of oscillating arms, and to indicate specific association with an embodiment or a variant by an exponent, for example “^(1a)” for the first embodiment (using a series of three oscillating arms), in its variant “a”. A reference numeral without any specific marker relates to a member which is always the same in the different variants or should be understood as designating without distinction all the variants of all the embodiments.

[0041] In the first embodiment shown in FIG. 1, the system of oscillating arms 3 ^(1a) comprises three functional oscillating arms 31 ^(1a), 32 ^(1a), 33 ^(1a) arranged in series and an auxiliary arm 34 ^(1a). This arrangement with three functional oscillating arms allows easy displacement of the guide member from one bead to the other and thus the obtainment, in conjunction with the presser devices 2 ^(G) and 2 ^(D), of operation of the apparatus from one bead to the other. An eyelet 6 constitutes in all the examples described here the materialization of the guide member for the cord 4 (without being limiting). The eyelet is always mounted on the last oscillating arm. Before going into detail, it should simply be pointed out that the system of oscillating arms 3 fulfils the function fulfilled by the chain system in above-cited patent, and the presser devices 2 ^(G) and 2 ^(D) are positioned in a suitable manner to play the role described in the above-cited patent.

[0042] The system of oscillating arms 3 ^(1a) is mounted on a plate 30 ^(1a) and causes the eyelet 6 ^(1a) to describe a movement flying over the core 1, and even passing round it in many embodiments. In all scenarios, the system of oscillating arms 3 causes the eyelet 6 to perform a movement in a plane. The eyelet 6 is flared: it forms a funnel with a large opening 61 on the side on which the cord 4 arrives and a smaller orifice 62 on the side on which the cord 4 exits (see also FIG. 3). It is the small orifice 62 which describes a movement in said plane of movement of the guide member. It is a good idea to take care over production of the edges of the orifice 62, so as not to damage the cord 4, since the outlet portion thereof is generally arranged substantially in the plane of movement, that is to say in a plane which is perpendicular to the guide direction imposed by the eyelet 6. As a variant, it is possible to orient the eyelet in such a way as to resemble the average orientation of the cord when leaving the eyelet.

[0043] The plate 30 ^(1a) comprises an oscillating shaft 3D^(1a) (see also 3D in FIGS. 10 and 11) motorizing the system of oscillating arms, the geometric axis of said oscillating shaft 3D^(1a) being situated radially outside the core 1. In other words, the geometric axis of said oscillating shaft 3D^(1a) is situated beyond the surface of the core 1, without the extension thereof coming into contact with the core 1. Said oscillating shaft 3D^(1a) does not effect continuous rotation, but rather oscillates within the limits of an arc smaller than 360°, the precise value depending on the exact constitution of the system of oscillating arms 3 and the intended use.

[0044] The entire oscillating arm system 3 itself is quite compact. All the depositing members, i.e. the oscillating arm system 3 and the presser devices 2, including the motor and the drive mechanism, form a sub-assembly capable of being easily presented to the core in a suitable manner, and capable of being retracted so that, for example, other devices may be presented to the core which are used for manufacture of a tire or for removal of the core to other tire building stations.

[0045] A base arm (or first arm) 31 ^(1a) (FIG. 1) is mounted on the oscillating shaft 3D^(1a) via a center of rotation 31R^(1a). The first arm 31 comprises a conveying head 31T^(1a) at the opposite end from the center of rotation 31R^(1a). A second arm 32 ^(1a), articulated by a center of rotation 32R^(1a) of the second arm, is mounted on the conveying head 31T^(1a) of the first arm 31 ^(1a). This second arm 32 ^(1a) comprises a conveying head 32T^(1a). So as to control the relative position of the second arm 32 ^(1a) relative to the first arm 31 ^(1a), in this example a parallelogram is formed by means of an auxiliary arm 34 ^(1a), mounted oscillatingly about an oscillating shaft 34D^(1a) via the center of rotation 34R^(1a) thereof. The center of rotation 34R^(1a) is situated radially outside the surface of the core 1, and radially between the latter and the center of rotation 31R^(1a) of the first arm 31 ^(1a). The auxiliary arm 34 ^(1a) comprises a conveying head 34T^(1a), articulated to the second arm 32 ^(1a) which comprises to this end an intermediate center of rotation 32I^(1a) situated between the center of rotation 32R^(1a) and the conveying head 32T^(1a) of said second arm 32 ^(1a).

[0046] It should be noted that it is not necessary for the singular points constituting the centers of rotation 31R^(1a), 34R^(1a) and the conveying heads 31T^(1a), 34T^(1a) to form a parallelogram. These points are preferably precisely aligned as they pass through the median position in the median plane, defined by the axis MM joining the centers of rotation 31R^(1a), 34R^(1a) and by the geometric axis of the shaft 3D (as well as by the geometric axis of the shaft 34D^(1a) which is naturally parallel with the former). In this way, the eyelet 6 describes a movement, the course of which is symmetrical with regard to this median plane, and it reaches the vicinity of each of the bead zones defined on the core 1 in a perfectly symmetrical movement, even in the control thereof. This does not of course exclude the ends of the eyelet movement from not being at symmetrical points relative to the median plane, for example for manufacturing a tire, the trajectory of the arches of which is not symmetrical. This would be the case in the manufacture of a tire whose diameters at the seat (usual term for designating the mounting seat) of each of the beads are different.

[0047] Finally, the apparatus comprises a third arm 33 ^(1a), articulated via its center of rotation 33R^(1a) to the conveying head 32T^(1a) of the second arm 32 ^(1a). This third arm 33 ^(1a) comprises a conveying head 33T^(1a), on which the eyelet 6 is directly mounted. Below, with the aid of FIG. 5, the control means will be described for the relative position of the third arm 33 ^(1a) with regard to the second arm 32 ^(1a), not shown in FIG. 1 so as not to overload the drawing. It should simply be noted, at this stage, that the use of such a third oscillating arm, mobile relative to the second oscillating arm, assists in advancing towards the beads the conveying end directly supporting the eyelet 6, that is to say assists in passing round the wall of the core 1 with regard to the center of rotation of the first arm, to arrive at zones hidden by said wall, undercut relative to the radial viewing direction. Finally, it should be pointed out that the relative orientation of the third arm 33 ^(1a) relative to the second arm 32 ^(1a) allows good visualization of the degree of functional freedom between said arms.

[0048] A motor 35 ^(1a) controls movement of all the arms 31 ^(1a), 32 ^(1a), 33 ^(1a), 34 ^(1a), preferably by motorization of the two shafts 3D^(1a) and 34D^(1a), as explained in detail by means of FIGS. 10 and 11. The motor 35 ^(1a) drives a disk 70 rotationally. A shaft 71 is mounted in the disk 70, in a predetermined eccentric position. The shaft 71 supports a roller 72. A carriage 73 moves translationally on slides 74 formed on the casing of the plate 30 ^(1a). The carriage 73 comprises a rectilinear slot 75, oriented perpendicularly to the direction of translation of the carriage 73 on the slides 74. A chain (with tension device) 76 is mounted on two identical pinions 77, and connected by its ends to the carriage 73. One of the identical pinions 77 is fixed to the shaft 3D and the other to the shaft 34D.

[0049] Assuming that the motor 35 imparts a rotational movement at constant speed to the control shaft 350, the roller 72 performs a circular movement 70R at constant speed. This being so, the roller 72 ascends and descends in the slot 75 and moves the carriage 73 translationally, thus converting a constant speed rotational movement into an alternating, linear to-and-fro movement, the speed of which varies sinusoidally. Through the intermediary of the chain 76 and the identical pinions 77, this alternating linear movement is converted at the shafts 3D and 34D into oscillations sweeping through an arc smaller than 360°. The amplitude of the oscillation may be adjusted by adjusting the radius at which the shaft 71 (thus the roller 72) is mounted eccentrically on the disk 70. It is of course possible to superimpose on the law of movement conversion thus created mechanically any control law specific to the rotation of the rotor of the motor 35.

[0050] Returning to the explanation of FIG. 1, a cord 4 is supplied via a spool (not shown) and is then wound onto a feed device 5 ^(1a) allowing the cord 4 to be fed and presented correctly to the depositing members. The feed device 5 ^(1a) preferably comprises means ensuring control of the tension of the cord 4 and, if applicable, the necessary compensation between the depositing members 3 ^(1a) and the spool, owing to the fact that the cord is adjusted by said depositing members to a cyclically variable speed, which may even be negative. The cord 4 is threaded into a first ring 51 ^(1a) disposed at some distance from the plane of movement, in which the eyelet 6 performs its cyclical movement. The ring 51 ^(1a) is disposed in a median manner with respect to the core 1. The cord 4 is then threaded into a ring 52 fixed to the second arm 32 ^(1a).

[0051] This cord 4 is threaded onto an eyelet 6. The eyelet 6 describes a to-and-fro movement from one bead to the other, or more precisely from a location close to one bead to a location close to the other bead. The basic functioning cycle of the apparatus according to the invention comprises the following stages:

[0052] with the cord being held against the form for a sufficient time, moving the eyelet (guide member) in an eyelet movement plane as far as a first end,

[0053] applying the cord to the form at this first end and holding it there for at least a sufficient time, by means of a presser device,

[0054] repeating the first stage in the opposite direction as far as a second end, applying the cord to the form at this second end and holding it there, by means of another presser device,

[0055] and thus repeating this basic cycle until the desired number of arches is deposited on the surface of the form, along the desired trajectory for the cord 4 on the surface of the form, by moving the form in synchronism with the movement of the guide member.

[0056]FIG. 2 shows more particularly the presser 2 ^(D) which comprises a fork 21 ^(D) and a hammer 22 ^(D), both of these being movable between a retracted position, at R (position remote from the core 1), and an advanced position, at A. Dash-dotted lines are used to show the hammer in the advanced position. With regard to the reference numerals in the Figures, the convention used is to designate each of the presser members with a main reference numeral, for example “21” for the fork, and to indicate specific association with the presser on one side (the left- or right-hand side in FIG. 1), respectively by the letter “^(G)” (left) or “^(D)” (right) positioned as an exponent. A reference numeral without any specific marker relates in generic manner without distinction to one or other of the pressers or their members.

[0057] Reference can be made to the appropriate part of the description of the above-cited patent to understand the respective functions of the fork and hammer 22 and the respective roles of the positions stated as advanced A and retracted R. FIG. 2 shows that both the fork 21 and the hammer 22 have the appearance of parallel blades. With respect to the hammer, the fork 21 is always disposed radially on the side of the axis of rotation of the core 1. The fork 21 has a V-shaped head 210, allowing the cord 4 to be taken up and centered. During the gripping phase, the plane formed by the “V” is disposed perpendicularly to the cord 4. When the cord 4 has to be arranged radially, as in FIG. 1, the blade forming the fork 21 is oriented at a tangent to a circle concentric with the core 1. The fork 21 also comprises a recess 211, the role of which will become apparent below.

[0058] It is known that the fork 21 is intended to bring the cord 4 against the core 1. To this end, the advancing movement thereof towards the core 1 is initiated when the eyelet 6 has brought the cord 4 to one end of the to-and-fro movement, that is to say when the apparatus is substantially in the configuration in FIG. 4. The fork 21 stops when it has anchored the cord in the rubber coating the core 1. Said fork 21 thus allows the cord 4 to be deposited with sufficient force for it to adhere correctly at the desired location. Returning to FIG. 1, and taking into account the laying pitch desired, which is itself a function of the rotational movement of the core 1 shown schematically by the arrow F, continuation of the movement of the system of oscillating arms 3 causes the formation of a loop around the tip 212, which begins the laying down of a new arch 40 on the core 1 (see FIG. 1). And passage of the eyelet 6 beyond the fork 21 during the return phase is permitted by the recess 211, although the fork 21 is positioned against the core 1 in this manufacturing stage. It should be pointed out that the size of the loop is a function of the dimensions of the tip 212.

[0059] The hammer 22 acts after the fork 21 and after the “return” phase of the eyelet 6. The hammer 22 presses on the cord 4 at a slightly higher radial position. Preferably it continues to hold the cord 4 while the fork 21 is retracted. The hold provided by the hammer during retraction of the fork assists in preventing the fork 21 from taking with it the loop of cord 4 which has formed about one of its tips 212 and which, even if it is stuck to the rubber, could have a tendency to remain attached to the fork. Anchoring of the cord 4 in the bead is thereby made perfectly reliable.

[0060] Of course, switching into the advanced position, and the return to the retracted position, are controlled, both for the fork 21 and the hammer 22, in synchronism with the system of oscillating arms 3 ^(1a), by any suitable device (return movement of the shaft 3D by a suitable mechanical transmission, for example using belts or cables, or by electrical synchronization between a plurality of motors). Hereinafter, such a device or its equivalent is simply shown schematically by an arrow and designated by reference numeral 2, it being understood that said numeral designates wholly generally a device with two acting elements, such as a fork and a hammer, acting in sequence on the cord 4.

[0061]FIG. 3 shows a variant of the same first embodiment, comprising a system of oscillating arms 3 ^(1b), differing from that described above essentially in the means of controlling the movement of the second arm 32 ^(1b) with regard to the base arm (or first arm) 31 ^(1b) In this variant of the first embodiment, the system of arms 3 ^(1b) again comprises three functional arms 31 ^(1b), 32 ^(1b), 33 ^(1b) arranged in series, and, in conjunction with presser devices, said control means also allow operation of the apparatus from one bead to the other. A base arm (or first arm) 31 ^(1b) is mounted on an oscillating shaft 3D^(1b) via a center of rotation 31R^(1b). The first arm 31 ^(1b) comprises a conveying head 31T^(1b) at the opposite end from the center of rotation 31R^(1b). A second arm 32 ^(1b), articulated by a center of rotation 32R^(1b) of the second arm, is mounted on the conveying head 31T^(1b) of the first arm 31 ^(1b). This second arm 32 ^(1b) comprises a conveying head 32T^(1b). Finally, the apparatus comprises a third arm 33 ^(1b), articulated via its center of rotation 33R^(1b) to the conveying head 32T^(1b) of the second arm 32 ^(1b). This third arm 33 ^(1b) comprises a conveying head 33T^(1b), on which the eyelet 6 is directly mounted.

[0062] A drive pulley 311 ^(1b) is shown centered on the center of rotation 31R^(1b) of said first arm. The drive pulley 311 ^(1b) is firmly connected to a flange 37 ^(1b) mounted fixedly on said plate (not shown in FIG. 3). A driven pulley 312 ^(1b) is firmly connected (that is to say without the possibility of any relative rotation) to the second arm 32 ^(1b). A toothed belt 361 ^(1b) connects said drive and driven pulleys. The diameters of the drive pulley and the driven pulley are identical so that, during movement thereof, the second arm 32 ^(1b) always remains parallel to itself. The person skilled in the art will have understood that, since it is a question of positioning the arm or various arms precisely, the pulleys used are toothed pulleys. The belts, which are also toothed, operate without relative sliding with respect to the pulleys on which they are mounted. It is of course possible to use any equivalent slide-free system to connect the arms whose position has to be controlled, such as for example a chain and pinions. In the present specification, the terms “pulley” and “belt” cover all equivalent systems for slide-free control of the relative positions.

[0063] In this example, the flange 37 ^(1b) is stationary in space but, more generally, it is important for the angular position thereof to be controlled independently of control of the oscillation of said first arm. It is possible, for example, to introduce a degree of freedom between the plate and the flange 37 ^(1b) and to control the relative position of said flange 37 ^(1b) relative to the plate, so as to act selectively on the spatial position of the drive pulley 311 ^(1b) in order, for example, to conform the movement performed by the eyelet 6 to different sized forms.

[0064] As far as the means of controlling the relative position of the third arm 33 ^(1b) relative to the second arm 32 ^(1b) are concerned, they essentially comprise a drive pulley 321 ^(1b) centered on the center of rotation 32R^(1b) of said second arm 32 ^(1b), firmly connected (no relative rotation possible) with the first arm 31 ^(1b), and they comprise a driven pulley 322 ^(1b) firmly connected (again, no relative rotation possible) with the third arm 33 ^(1b). A toothed belt 362 ^(1b) connects said drive and driven pulleys. The diameters of the drive pulley and the driven pulley are different, their respective values being calculated so that the conveying end 33T^(1b), during movement thereof, reaches the zone of the core 1 close to the bead (see FIG. 4) without the second arm 32 ^(1b) striking the sidewall 11 of the core 1.

[0065]FIG. 4 shows the eyelet 6 in the position 6(a) imposed by the above-described apparatus, at one end of the to-and-fro movement of the functional oscillating arms 31 ^(1b), 32 ^(1b), 33 ^(1b). The corresponding configuration adopted by the second and third arms of the apparatus is shown at 32 ^(1b)(a) and 33 ^(1b)(b) respectively. Various other positions and configurations are designated by the reference letters (b), (c), (d).

[0066] As a variant, the drive pulley 321 ^(1b) could also be mounted freely with respect to the first arm 31 ^(1b) and driven by a belt wound on the one hand around a pulley firmly connected with said drive pulley 321 ^(1b) and on the other hand wound round another pulley (not shown) concentric with the geometric axis 3D^(1b) and motorized independently both of the movement of the first arm and of the movement of the pulley 311 ^(1b). This provides more latitude when it comes to controlling the relative movement of the third arm relative to the second.

[0067]FIG. 5 illustrates an equivalent control means, mounted on the system of oscillating arms 3 ^(1a) of FIG. 1. This Figure shows a third pulley 321 ^(1a) centered on the intermediate center of rotation 32I^(1a) of said second arm 32 ^(1a), firmly connected (no relative rotation possible) with the intermediate arm 34 ^(1a), and a fourth pulley 322 ^(1a) firmly connected (again, no relative rotation possible) with said third arm 33 ^(1a). A toothed belt 362 ^(1a) connects said drive and driven pulleys. The diameters of the drive pulley and the driven pulley are different, their respective values being calculated so that the conveying end 33T^(1a), during movement thereof, reaches the zone of the core 1 close to the bead (see FIG. 4) without the second arm 32 ^(1a) striking the sidewall 11 of the core 1. The previous comment about another possibility for controlling the relative movement of the third arm relative to the second also applies to this variant.

[0068] Emphasis should also be laid on another detail which is readily visible in FIG. 5. In this Figure, the system of arms 3 ^(1a) is substantially configured as in FIG. 1. In this configuration, the second arm 32 ^(1a) is on one side of the first arm 31 ^(1a) and the intermediate arm 34 ^(1a) (and on one side of the median plane defined by the axis MM and the geometric axis of the shaft 3D^(1a)) and remains on this side during the part of the movement during which the eyelet 6 flies over the half of the core 1 situated on one side of said median plane. During the movement from one side of the core to the other side, the second arm 32 ^(1a) is caused to pass to the other side of the median plane and, in doing this, to the other side of the first arm 31 ^(1a) and the intermediate arm 34 ^(1a). During the same movement, the intermediate arm 34 ^(1a) passes over the first arm 31 ^(1a). It is thus important for the arms to be correctly superposed so that this movement is possible. This is the role of the distance sleeves 381 ^(1a) and 382 ^(1a). It goes without saying that this comment is of general application. The oscillating arms articulated to each other, insofar as they perform a movement symmetrical in its course relative to a median plane, have to be superposed judiciously relative to one another to allow all the desired crossings of the arms.

[0069] With reference to FIGS. 6 and 7, another variant of the first embodiment will now be explained, said variant again relating to control of the movement of a third arm 33 ^(1c). In this further variant of the first embodiment, the system of arms 31 ^(1c) again comprises three functional arms 31 ^(1c), 32 ^(1c), 33 ^(1c) arranged in series, and, in conjunction with presser devices, said control means also allows operation of the apparatus from one bead to the other.

[0070] The Figures show a base arm (or first arm) 31 ^(1c) and a second arm 32 ^(1c), a description of the relative movement between the first and second arms being superfluous since it may be identical to that which has been described for the system of arms 3 ^(1a) or 3 ^(1b). The first arm 31 ^(1c) comprises a conveying head 31T^(1c). A second arm 32 ^(1c), articulated by a center of rotation 32R^(1c) of the second arm, is mounted on the conveying head 31T^(1c) of the first arm 31 ^(1c). This second arm 32 ^(1c) comprises a conveying head 32T^(1c). Finally, the apparatus comprises a third arm 33 ^(1c), articulated via its center of rotation 33R^(1c) to the conveying head 32T^(1c) of the second arm 32 ^(1c). This third arm 33 ^(1c) comprises a conveying head 33T^(1c), on which the eyelet 6 is directly mounted. A cam 381 ^(1c) is machined into the conveying head 31T^(1c) of the first arm 31 ^(1c). The cam comprises a neutral portion 381N^(1c) machined with a constant average radius, a final control portion 38A^(1c) with an increasing radius, for controlling the relative movement of the third arm 33 ^(1c) on one side of the core, and a final control portion 381B^(1c) with decreasing radius, for controlling the relative movement of the third arm 33 ^(1c) on the other side of the core. A toothed wheel 322 ^(1c) is mounted on the center of rotation 33R^(1c) of the third arm 33 ^(1c) and is firmly connected (no relative rotation possible) with said third arm 33 ^(1c). A connecting rod 383 ^(1c) slides in a guide 384 ^(1c) firmly connected with the second arm 32 ^(1c). The connecting rod 383 ^(1c) is thus guided in sliding manner with respect to the second arm 32 ^(1c). The connecting rod 383 ^(1c) carries on one side a cam follower 382 ^(1c) cooperating with said cam 381 ^(1c). On the opposite side from the cam follower 382 ^(1c), the connecting rod 383 ^(1c) comprises a rack 385 ^(1c) which is engaged on said toothed wheel 322 ^(1c). The profile of the cam in the final control portions 381A^(1c) and 381B^(1c) is selected so that, during movement of the third arm 33 ^(1c), the eyelet 6 mounted on the conveying end 33T^(1c) of said third arm 33 ^(1c) reaches the zone of the core 1 close to the bead (see position 6 a in FIG. 7) without the second arm 32 1b striking the sidewall 11 of the core 1.

[0071]FIG. 7 shows the eyelet 6 in the position 6(a′) imposed by the above-described cam apparatus, at one end of the to-and-fro movement of the functional oscillating arms 31 ^(1c), 32 ^(1c), 33 ^(1c). The corresponding configuration adopted by the second and third arms of the apparatus is shown at 32 ^(1c)(a′) and 33 ^(1c)(a′) respectively. Various other positions and configurations are designated by the reference letters (b′), (c′), (d′). By comparing FIGS. 4 and 7, it will be noted that, if the positions marked (a) and (a′) are identical, the positions marked (b′), (c′) and (d′) in FIG. 7 differ somewhat from the positions (b), (c) and (d) in FIG. 4. The considerably greater clearance at the level of the sidewall 11 will be noted, said clearance being maintained and permitted by the cam control means.

[0072] Due to the cam control, the relative movement between the second and third arms may be fairly freely conformed to requirements since it depends essentially on the profile of the cam. The constraints of proportionality with regard to the relative rotary movement between the first and second arms, specific to the belt control described with reference to FIGS. 3 and 5, are thus removed. It is possible to impose a relative position of the third arm with regard to the second arm, in particular in order to disengage the eyelet 6 rapidly with respect to the core 1. In this way, a constantly sufficient clearance is ensured between the conveying head 33T^(1c) and the core 1 (see positions 6 b, 6 c and 6 d) while moving sufficiently close to the surface of the core 1 in the bead zone (see position 6 a). On the cam 381 ^(1c), it may be noted that the part 381B^(1c), and the part 381D^(1c) deflected in the other direction, impose considerable changes in position over only a short distance, i.e. rapid changes in position (travel being in a curvilinear x-direction along the cam 381 ^(1c)), to tilt the third arm 33 ^(1c) respectively to one side and the other of the second arm 32 ^(1c), at the opposite ends of the movement of the eyelet 6, when it approaches each of the beads.

[0073] In a second embodiment, illustrated in FIGS. 8 and 9, the system of oscillating arms 3 comprises two functional oscillating arms 31 ^(2a) and 32 ^(2a) in series. It is designed for operation from a bead to a shoulder, for example for manufacture of a half-carcass. It is known, in effect, that the carcass of a radial tire may be discontinuous from one bead to the other, being interrupted somewhere under the tread, the belt reinforcement ensuring the transmission of forces between the half-carcasses. The carcass reinforcement must be deposited between the bead and a shoulder. The oscillating arm system 3 ^(2a) adopts the parallelogram principle used in the oscillating arm system 3 ^(1a), except that, of course, there is no third arm. A plate 30 ^(2a) supports a control motor 35 ^(2a). The control motor 35 ^(2a) actuates shafts 3D^(2a) and 34D^(2a), the geometric axis of rotation of which is included in a median plane M^(2a)-M^(2a). The control motor 35 ^(2a) also actuates the presser devices 2 ^(G) and 2 ^(D), these being of the same type as those described in more detail in relation to FIG. 2. The spacing of the presser devices 2 ^(G) and 2 ^(D) relative to the median plane M^(2a)-M^(2a) may be adjusted by wheels 23 ^(2a) and 24 ^(2a).

[0074] A base arm (or first arm) 3 ^(2a) is mounted on the oscillating shaft 3D^(2a) via its center of rotation 31R^(2a). Taking as the reference point the center C of the radial section of the core 1, the center of rotation 34R^(2a) is situated externally of the surface of the core 1. The first arm 31 ^(2a) comprises a conveying head 31T^(2a). A second arm 32 ^(2a), articulated by a center of rotation 32R^(2a) of the second arm, is mounted on the conveying head 31T^(2a) of the first arm 31 ^(2a). This second arm 32 ^(2a) comprises a conveying head 32T^(2a). So as to control the relative position of the second arm 32 ^(2a) relative to the first arm 31 ^(2a), in this example a parallelogram is formed by means of an auxiliary arm 34 ^(2a), mounted oscillatingly about the oscillating shaft 34D^(2a) via the center of rotation 34R^(2a) thereof. Taking as the reference point the center C of the radial section of the core 1, the center of rotation 34R^(2a) is situated externally of the surface of the core 1, between the latter and the center of rotation 31R^(2a) of the first arm 31 ^(2a). The auxiliary arm 34 ^(2a) comprises a conveying head 34T^(2a), articulated to the second arm 32 ^(2a) which comprises to this end an intermediate center of rotation 32I^(2a) situated between the center of rotation 32R^(2a) and the conveying head 32T^(2a) of said second arm 32 ^(2a). The conveying head 32T^(2a) of the second arm 32 ^(2a) directly supports the eyelet 6. The movement of the eyelet 6 is shown by the axis line 63 ^(2a).

[0075] An apparatus according to this principle, with two functional oscillating arms, could just as well be used for operation from a bead as far as any point under the tread, including as far as the opposing shoulder, with a certain degree of overlap between the half-carcasses.

[0076]FIG. 9 shows a variant comprising a system of oscillating arms 3 ^(2b), differing from that described in relation to the system of FIG. 8 essentially in the means of controlling the movement of the second arm 32 ^(2b) with regard to the base arm (or first arm) 31 ^(2b). Instead of a control means comprising toothed pulleys and belts, this variant comprises a drive pinion 311 ^(2b) centered on the center of rotation 31R^(2b) of said first arm.

[0077] The Figure shows a base arm (or first arm) 31 ^(2b) mounted on an oscillating shaft via its center of rotation 31R^(2b). The first arm 31 ^(2b) comprises a conveying head 31T^(2b) at the opposite end from the center of rotation 31R^(2b). A second arm 32 ^(2b), articulated by a center of rotation 32R^(2b) of the second arm, is mounted on the conveying head 31T^(2b) of the first arm 31 ^(2b). This second arm 32 ^(2b) comprises a conveying head 32T²b, on which the eyelet 6 is directly mounted. The drive pinion 311 ^(2b) is firmly connected with a flange 37 ^(2b) mounted fixedly on a plate (not shown in FIG. 9). A driven pinion 312 ^(2b) is firmly connected (that is to say without the possibility of any relative rotation) to the second arm 32 ^(2b). A chain 361 ^(2b) connects said first and second pinions. The diameters of the first and second pinions are identical so that, during movement thereof, the second arm 32 ^(2b) always remains parallel to itself. The arm system 3 ^(2b) may replace the arm system 3 ^(2a) of FIG. 8. The above comment about the possibility of controlling a degree of freedom between the plate and the flange 37 ^(1b) and controlling the relative position of said flange 37 ^(1b) relative to the plate also applies to the flange 37 ^(2b), as well as to all similar flanges.

[0078] It should be remembered that the eyelet 6, in all the variants, is actuated with a cyclical movement in a plane, designated above as “the plane of movement”. Moreover, the pre-coated surface of the core 1 determines the overall geometry of the surface on which the reinforcing cord 4 is deposited. Furthermore, the core 1 is driven rotationally about its axis while the eyelet 6 performs its to-and-fro movements in the plane of movement of the eyelet. Of course, the movement of the core 1 is synchronized with the to-and-fro movement of the eyelet. The true trajectory of the arches 40 of the cord 4 is thus both a function of the relative position between the eyelet movement plane and the core and a function of the relative movement between the core 1 and the to-and-fro movement of the eyelet 6.

[0079] In FIGS. 1, 4, 7 and 8, the trajectory of the arch 40 is substantially radial, because said Figures apply to the production of a carcass (or a half-carcass) for a radial tire, without this being limiting, of course. Another example is given in a third embodiment, illustrated in FIG. 12, where the trajectory of the arch 40 ^(3a) is not radial but rather forms an angle typical of belt reinforcements (of the order of 15° to 30°).

[0080] In this third embodiment shown in FIG. 12, a system is disclosed which comprises a single functional oscillating arm (the base arm) 31 ^(3a), adapted for example to the production of reinforcements in the belt of a tire. It is adapted, for example, to shoulder to shoulder operation, to produce belt reinforcements. The base arm 31 ^(3a) is mounted on an oscillating shaft 3D^(3a) via its center of rotation 31R^(3a). The base arm 31 ^(3a) comprises a conveying head 31T^(3a), to which an eyelet 6 is directly attached. The plane of movement in which the eyelet 6 describes its to-and-fro movement forms an angle of the order of 20° relative to a plane perpendicular to the axis of rotation of the core 1, according to the conventions usual for measuring angles in the tire sector. The presser devices 2 ^(G) and 2 ^(D) act in the same plane of movement. Among the details visible in FIG. 12 which are not specific to this embodiment, it should be noted that the cord 4 is passed through the hollow center 5 ^(3a) of the oscillating shaft 3D^(3a) and that a large return capacity compensation system 52 ^(3a) is installed upstream.

[0081] To produce a carcass with cross-ply in the sidewalls, the eyelet plane of movement may be changed from a purely radial orientation by inclining the depositing member support (such as the plate 30) about an axis parallel to the axis of rotation of the core 1. It is of course possible to combine this adjustment with that applied in the above paragraph illustrating the production of belt reinforcements. It is also possible, without changing any features of the members of the apparatus as described, to drive the core at a fairly high speed, for example {fraction (1/8)} of a revolution per to-and-fro movement of the arm system 3, in such a way that a cord laying angle is obtained which is a function of the relationship between the speed of the chain and the speed of the core (whereas in all the preceding examples the speed of the core 1 affected only the laying pitch).

[0082] The following comment explains an additional variant, which may be applied to all the embodiments described here, in all the variants thereof. It is possible to impart an alternating movement to the depositing member support (such as the plate 30 ^(1a)—see FIG. 1) with the purpose of deflecting the trajectory of the cord 4 on the core 1. It is possible, for example, to actuate the depositing member support with an alternating translational movement (see double arrow P in FIG. 1), allowing translation of the eyelet plane of movement in a direction perpendicular to the plane of movement. It is also possible to actuate the depositing member support with an oscillatory movement about a geometric axis perpendicular to the surface of the form, included in the plane of movement and intersecting the geometric axis of rotation of the base arm (see double arrow Q about the axis M-M of FIG. 1), allowing oscillation of the plane of movement about an axis parallel to said plane of movement. It is also possible to actuate the depositing member support with an oscillatory movement about any axis parallel with the previous one. It is important to distinguish such a design from simple fixed adjustment (also possible and useful in certain cases) of the angle which the plate 30 ^(1a) forms about the axis MM. All these particular embodiments provide an additional degree of freedom for acting on the exact shape of the trajectory of the cord 4.

[0083] An advantage of the invention is that the apparatus thus performing the previously known basic process is mechanically simple and light and that this apparatus involves at most only adjustments which are simple to perform for adaptation to all the tire reinforcement variants to be produced, covering the widest possible range of tires. The system of oscillating arms exhibits little protrusion, little inertia and lends itself well to elevated operating speeds.

[0084] It is possible to produce a carcass reinforcement in several (n) depositing passes, each pass covering the entire core. Since the radial arches within one pass are laid down at a pitch P, the position on the core 1 of the arches 40 laid down during n successive passes may thus exhibit a circumferential phase shift corresponding to P/n. The person skilled in the art may also foresee a plurality of ways of using the invention, depending on the tire architecture which it is desired to obtain.

[0085] It should also be pointed out that, in the case of the production of half-carcasses (see FIGS. 8 and 9), it is possible to produce each of the half-carcasses simultaneously each side of the core, by providing two apparatus according to the invention, each opposite one side of the core. Or it is possible to produce each of the half-carcasses in succession.

[0086] An advantage of the present invention is that is allows passage round the form in numerous instances of use, including ones in which the trajectory of the arches forms an angle very different from 90° (for example of the order of 20°). Even in this instance, it is also possible to reach two points of the form in succession, each in the zone corresponding to a tire bead, without the risk of striking the form. 

I claim:
 1. An apparatus for manufacturing a tire reinforcement, said apparatus being intended for manufacturing a reinforcement constituted from a cord supplied continuously and on demand by a suitable distributor, said apparatus being intended for use in cooperation with a substantially toroidal form on which said reinforcement is built up progressively by laying down arches of said cord, according to a desired trajectory for said cord, on the surface of said form, said apparatus comprising: a guide member in which the cord may slide freely, means for displacing said guide member in a cyclical, to-and-fro, movement, to bring said guide member in successive cycles into the vicinity of each of the desired ends for the cord in said trajectory, pressers close to each end of said trajectory, for applying the cord onto the form at said ends, characterized in that: the displacement means comprises at least one base arm, said base arm comprising a center of rotation and a conveying head, and control means for imparting to said base arm an oscillatory movement about said center of rotation, the apparatus being arranged so that the conveying head of said base arm conveys the guide member from one end to the other of said trajectory, the geometric axis of said center of rotation is, in the working position, entirely exterior to the form.
 2. An apparatus according to claim 1 , in which the conveying head of the base arm directly supports said guide member.
 3. An apparatus according to claim 1 , comprising a second arm, articulated on a center of rotation of the second arm, said center of rotation of the second arm being mounted on said conveying head of said base arm, said second arm having a conveying head for conveying the guide member from one end to the other of said trajectory, and comprising control means for controlling the relative position of the second arm relative to said base arm.
 4. An apparatus for manufacturing a tire reinforcement, said apparatus being intended for manufacturing a reinforcement constituted from a cord supplied continuously and on demand by a suitable distributor, said apparatus being intended for use in cooperation with a substantially toroidal form on which said reinforcement is built up progressively by depositing arches of said cord according to a desired trajectory for said cord on the surface of said form, said apparatus comprising: a guide member in which the cord may slide freely, means of displacing said guide member in a cyclical, to-and-fro, movement, to bring said guide member in successive cycles into the vicinity of each of the desired ends for the cord in said trajectory, pressers close to each end of said trajectory, for applying the cord onto the form at said ends, characterized in that the displacement means comprise at least two arms, i.e. an oscillating base arm and at least one other oscillating arm, said at least two arms each comprising a center of rotation and a conveying head, said at least two arms each oscillating about a geometric axis of rotation, said geometric axis of rotation being parallel to each other, and control means for imparting to said arms oscillatory movements about the respective geometric axes of rotation thereof, the apparatus being arranged so that the conveying head of said base arm conveys the center of rotation of a second oscillating arm and so that the conveying head conveys the guide member from one end to the other of said trajectory, the apparatus comprising control means for controlling the relative position of the second arm relative to said base arm.
 5. An apparatus according to claim 3 or claim 4 , in which said control means for controlling the relative position of the second arm relative to the base arm comprise a drive pulley centered on the center of rotation of said base arm, the angular position of said drive pulley being controlled independently of the oscillation control of said base arm, and comprise a driven pulley firmly connected with said second arm, a toothed belt connecting said pulleys.
 6. An apparatus according to claim 5 , in which said drive pulley is stationary in space.
 7. An apparatus according to claim 1 , comprising a second oscillating arm, the center of rotation of the second arm being mounted at the conveying end of said base arm, said second arm having a conveying head for conveying the guide member from one end to the other of said trajectory, and comprising an auxiliary arm oscillating about a center of rotation, the geometric axis of rotation of said center of rotation of the auxiliary arm being situated entirely exterior to the surface of the form, between the latter and the geometric axis of rotation of said base arm, said auxiliary arm having a conveying head, said second arm having an intermediate center of rotation between the center of rotation of the second arm and the conveying head of said second arm, said intermediate center of rotation being articulated on the conveying head of said auxiliary arm.
 8. An apparatus according to claim 3 , in which the conveying head of the second arm directly supports said guide member.
 9. An apparatus according to one of claim 3 or 4 , comprising a third oscillating arm, articulated by its center of rotation to the conveying head of the second arm, said third arm having a conveying head for conveying the guide member from one end to the other of said trajectory, and comprising control means for controlling the relative position of the third arm relative to the second arm.
 10. An apparatus according to claim 9 , in which the conveying head of the third arm directly supports said guide member.
 11. An apparatus according to claim 9 , in which said control means for controlling the relative position of the third arm relative to the second arm comprise a drive pulley centered on the center of rotation of said second arm, said drive pulley being firmly connected with the base arm, and comprise a driven pulley firmly connected with said third arm at the center of rotation thereof, a toothed belt connecting said drive and driven pulleys.
 12. An apparatus according to claim 9 , in which said control means for controlling the relative position of the third arm relative to the second arm comprise a drive pulley centered on the intermediate center of rotation of said second arm, said drive pulley being firmly connected with the intermediate arm, and comprise a driven pulley firmly connected with said third arm at the center of rotation thereof, a toothed belt connecting said drive and driven pulleys.
 13. An apparatus according to claim 9 , in which said control means for controlling the relative position of the third arm relative to the second arm comprise a cam arranged in the conveying head of the base arm, a toothed wheel firmly connected with the third arm, a connecting rod guided in sliding manner with regard to the second arm, carrying on one side a cam follower cooperating with said cam and on the other a rack engaged on said toothed wheel.
 14. An apparatus according to claim 1 , comprising a support for the means of displacing said guide member and comprising means of imparting to said support an alternating movement allowing deflection of the trajectory of the cord on the core. 